The present invention relates to an improved molding machine, in particular, a two faced index molding machine, having improved part cooling and part removal.
Index molding machines are known in the art. U.S. Pat. No. 5,728,409, assigned to the assignee of the instant application, shows a four faced turret block with a temperature conditioning station mounted to the turret for directing cooling air onto newly molded articles and a tubular part removal system using an air conveyor. Currently, there is a need for a lower cost molding machine which employs only a two faced turret block and correspondingly half the number of core sets of tooling.
Co-pending, allowed U.S. patent application Ser. No. 08/847,895 to Arnott et al., entitled Injection Molding Machine Having a High Speed Turret, filed Apr. 28, 1997, also assigned to the assignee of the instant application, shows an index molding machine with a two faced turret block. This application however does not discuss the problems of part cooling and controlled part removal.
Co-pending U.S. patent application Serial No. 09/070,598, to Galt et al., filed Apr. 30, 1998, entitled Tiebar Structure for Injection Molding Machine, also assigned to the assignee of the instant application, shows a two tiebar index molding machine. Here again, there is no discussion of part cooling or part removal.
U.S. Pat. No. 4,729,732 and U.S. Reissue Pat. No. 33,237, both assigned to the assignee of the instant application, show a multi-position tooling plate with water cooled tubes used to remove and cool preforms from a conventional preform molding machine. The tooling plate design shown in these patents has two disadvantages. First, the robot mechanism occupies a substantial floor area adjacent the machine. Second, the preforms are cooled inside their tubes in a horizontal orientation. This has been found to be detrimental in that the weight of the preform causes it to press more firmly against the lower portion of the cooling tube while its upper surface tends to separate from the upper portion of the cooling tube. This unequal contact force with the cooling surface tends to promote unequal cooling of the preform from one side to the other. A vertical orientation during cooling provides a symmetrical weight distribution with a balanced heat removal result.
Conventional index molding machines eject parts at the lowermost station, i.e., when the molded parts to be ejected are under the turret block. There is a need to accommodate part ejection/removal at a station opposite to the molding station to permit two faced turret operation in a molding cycle where the turret rotates 180 degrees each time the mold opens instead of rotating 90 degrees at each mold opening.